The present invention relates to a clearing chain for excavating bulk material from a ballast bed supporting a track and for conveying the excavated bulk material, and more particularly to a clearing chain of a type including a plurality of shovel-type clearing members sequentially arranged in the direction of elongation of the chain for gathering and moving along the bulk material, the chain being mounted on a frame of a mobile track working machine.
U.S. Pat. No. 4,614,238 discloses an articulatedly constructed clearing chain of this type which is composed of a multitude of similarly formed chain elements connected to one another by means of respective chain joints. Every third chain element is connected by means of a screwed connection to a clearing element designed for excavating or collecting bulk material. The chain joints are shaped as universally movable cross joints. Such a flexible clearing chain can be guided in a three-dimensional path; however, the structural design required for this purpose is relatively complicated.
It would therefore be desirable and advantageous to provide an improved clearing chain which obviates prior art shortcomings and which, while retaining the feature of universally movable joints, can be manufactured in a simple manner.
According to one aspect of the present invention, a clearing chain includes intermediate chain elements positioned in each case between two adjacent clearing members for forming an endless chain, each intermediate chain element including two chain joints spaced from one another in the direction of elongation of the chain, each chain joint having a joint axis; and hinge pins for hingedly connecting the clearing members and intermediate chain elements to one another at each chain joint, the hinge pins being releasably fastened to the clearing member and articulatedly mounted in the chain joint.
This particular design of the clearing chain, being composed of clearing members and intermediate chain parts alternatingly following one another in the direction of longitudinal extension of the chain, already results in a simplification of the structural complexity of the chain. An additional advantage is due to the circumstance that the individual clearing members have no moving or articulated parts and therefore can be manufactured in a simple manner, producing a sturdy component which is particularly suited for robust use under diverse conditions.
Preferably, the chain joint includes a joint bearing designed as a spherical bearing, including a knuckle eye and a ball race which is universally movably mounted in the knuckle eye and surrounds the hinge pin extending in the direction of the joint axis. This feature provides the required degree of flexibility to guide the chain in a three-dimensional manner while ensuring simplicity and robustness of design.